I'll try another epub later today and report back. Also, not sure why some of the responses are talking about the original kobo. This problem affects the wifi with firmware 1.7.4. Maybe some people have gotten used to the lag but trust me, the kobo (wifi) page turns are taking 1-3 seconds when a kindle is instantaneous.

I would be really disappointed if my Kobo took 3 seconds to flip pages.

For what it's worth, I've been reading a LOT on my Kobo Wifi lately and I find it takes maybe one full second from the time I press the button to the time I'm reading the next page. As as been previously mentioned, that's about how long it takes me to turn a page in real life so it feels really natural. To me it looks like the speed is limited by the current state of eInk technology more than anything.